Glass-casting table.



'L W." CDRDES. GLASS GASTIMG TABLE Mmcmmm mm mov. 2o mm.

WITNESSES z sTATNs PNTNNT uniba.-

` .tonie W. connus, or PITTSBURGH, PENNSYLVANIA, AssIGNon `To PITTSBURGH PLATE l I GLMSS OMPNY, OF IJETTSBURGH, PENNSYLVANIA, A CORPORATION 0F PENNSYL- 'VMM- a mcafee?, 1

To all vmay concern Be -it known that I, JOHN W. CORDES, a

citizen of the United States, residing at Pittsburgh, iny the county of Allegheny and State of Pennsylvania, have :invented a certain new andA useful Glass-Casting Table, of

' which the followingis a specification.

flo

the making'of plate glass.

The invention relates to tables for use in It has for its primary objects; the provision of a table surfaced so that the` rapidity of,4 heat trans- .ference from the glass to thel table is rev plan View ofthe surface of the table magnilied to show its roughness, Fig. 3 is a section on the line Ill-.Ill of Fig. 2, Fig. l4 is a section on the line 'lV-IV'of Fig. 2, and Fig. v5 is' a diagrammatic plan view` of a por tion vof atable having a modified type of roughening.

` The present method of casting plate glass involves the use of 'leers-"at the ends of the casting tables to receive the sheets of .glass after the casting operation and as a result, upon the saine endof any. particular table, that is, upon the. end of the tablev remote from the leer. Re-

the glass is always poured peated` use of the' table tends to causegan overheating thereof, especially at the end sult the table will liftand warp and adher- V which receives the molten glass, and as a re- `ence of the glass -to the table will occur unless means are'provided .to prevent 1t. 'llhe .prevention of this overheating of the tables has been accomplished by water coohng, but

i thisy water cooling, because of the rapid transference ofthe heatbf the glass to the surface of the table, tends to produceline cracks, called pin cracksfin thesurface of the glass in contactv withfthe metal. To avoid'this difliculty and reduce the rapidity of cooling'at the surfaceof thegl'ass, a thin layer of sand has been used upon the' table, -and in this manner the vtable is not only prevented from overheating,v but. thei pin cracks in thel surface of'. the' glass are avoided.' The ci the sand,z hewever, is.

Specification of Letters Patent,

Grass-CASTTNG TABLE.l

Patented Dec. llullgll..

Application led November 20, 1914. Serial No. 873,082.

subjecttoa disadvantage that its use nec essarlly roughens the face of the sheet o glass to which it sticks so that more grind-i ing is required than would 'otherwise be,

necessary if a smooth surface were used'i vwithout sand, and because of this excessivef grinding a lthicker sheet o'f glass mustbe cast. Also the presence of the 4'particles of sand adhering to the surface presents certain objections in the handling of the glass by the modern methods by means of clamps as'the grains embed themselves inthe face of the clamps and itis necessary to grind. the sand Y the use of lsand or of al similar material, and

is directed to the feature of so surfacing the casting table that the rapidity of heat transference from the glass to the table `is remitting at the Sametime of thel use of the water cooling feature, Whichprevents the table from warping or becoming overheated. Briefly stated, I accomplish this result by very: nely roughening the surface of the table, thus producing a multitude of minute duced without the use of sand, thus perdepressions of such smallness that the glass is substantially excluded therefrom, such eX- clusion being largely due, I believe, to the' presence of air entrapped in 'the depressions. The areaof contact ybetween-v the glass and .the metal is thus veryulargely reduced and` as. a result the rapidity ofheattransference from the glass to the metal is greatly reduced. "As a result the table may. beso Water f cooledthat it will 'not warp or overheat, and at the same timeany cracking of theglass due'tothe too rapid coolingl of its surface is avoided; The use of sand isthus avoided, and a substantially' smooth surface upon the glass is secured since the roughening of, the

.surface of the table does not result in the 'roughening of the surface of the glass.

' securing of'a smooth surface of the glass is further helped-by the use ofa thin coating of ,plumbago upon the surface of the table such The i:

, plumbagq .filling in the dl@pres/S1,011s ami rem dering the surface of the table substantially smooth. y The use of plumbago (which is not broadly new upon casting tables since it had been heretofore used to polish tables with smooth surfaces prior to the advent of water cooled tables) is further advantageous in ture, havingless conductivity than metal of greater density and .finer texture, and is more readily roughened in the machining operation as hereafter described than is the casewith 'a more dense and finer grained metal. The glass receiving 'surface 3 of the table is very finely roughened.' This is preferably accomplished inthe machining operation upon a planer.y The tool employed in machining the surface, is given a v feed which Ais heavier than normal and as I form.4 Itwill be seen that the a result the tool does not cut smoothly, but toa lcertain extent .tears off the ribbon of metal, leaving the surface machined finely roughened with minute transverse grooves or depressions, such action being well known to machinists and characteristic ofthe taking of an unduly heavy cut either upon a planer or 4lathe thev ,cells resulting being larger than the holes leading to them which forms an `ideal surface to hold the air or unguent, as hereafter described, imprisoned. The character of the surface secured is indicated graphically in Fig. z2, the parallel lines 4 indicating the lines of travel of the edges of the tool, and the fine transverse lines of relatively short length indicating the depressions due to the tearing action of the tool upon the metal. A s indicated at 5 in Fig. 4,.'-the small transverse grooves are very minute and closely spaced, while as indicated at 4 inV Fig. 3 the grooves between the lines 4,. (Fig. 2.) are larger and more uniroughening effect as secured bygthe machining operation, is a very fine one, the depressions being so minute as to hold a quantity of air and exclude the moltenglass, without perceptibly roughening the surface of the glass.

The method above described for secur-v ing the roughenedsurface .upon the table is only one of many which might be employed and coming within the scope of the invention, such method, however, being preferred because of the ease with which the roughening is secured and because the surface secured is perfectly suited to obtain the desired'results. A more regular roughening A ofthe surface might be secured by. knurling eater by planing roughly rst in one direction and then transversely as indicated in Fig.

The invention of course has its greatest ditions it may be dispensed with. or other unguent, relatively non-conductingmaterials, may be employed in place of the plum-l bago, such as graphite, red oXid of iron, or the like. I have found by the use of this ,table that a relatively smooth sheet of glass may be cast upon ay water cooled table without the cracking of the surface of the glass,

such sheet being thinner and requiring less grinding than is possible by the use of a similar table but employing sand in place of the roughened surface. I have also found that the table is more durable than in the case where sand is employed and that the sheet may be more easily-slid off of the table into the leer than is the case with the standard table wherein the sand resists the movement of the sheet of glass and tends to wear the table. Other advantages incident to the construction will be readily apparent to those skilled in the art.

What I claim is:

1. A castingA table having a metal glass receiving surface roughened with a degree of fineness such as to reduce the area of contact between the glass and metal while at the same time givingya substantially smooth surface to the glass cast upon the surface.

2. A water cooled casting table of metal having its glass receiving surface roughened with a degree of ne'ness such as to reduce the area of contact between the glass and metal while at the same time giving a substantially smooth surface to the glass cast upon the surface.

3. A casting table of metal having a metal glass receiving surface substantially plain but covered with minute depressions of such smallness that the molten glass is substantially excluded therefrom.

4. A casting table of metal having its glass receiving surface finely roughened so as to provide minute depressions and projections, and a coating of unguent relatively refractory material on the said surface filling the said depressions and rendering such surface smooth.

5. A water cooled casting table of metal having its glass receiving surface substantially plain butcovered with minute depressions of such smallness that the molten glass is substantially excluded therefrom.

6. A'wat'er cooled casting table of metal havingxits' glass receiving surface finely roughened so as to provide minute depressions `projections, and a coating of unguent relatively r frac-tory material on the said surface filling' the said depressions and rendering such surface smooth.

7. casting table of metall lmving vo/:u'se porous texture and provided with n.' glass receiving surface finely rougliened so :is to provide 'minute depressions and projections, and :L coating of unguent relatively refrneting nllzlterial on' the sai-id surface {ill- 10 ing the said depressions and renderingsuch -sm'fuce smooth.

8. A casting table of metal having lts glass receiving `surface machined with 'a tooled to a cutof such heavmess that the metal is partially tom oil' leziving the surface subl5 stnntiully .plain but finely :1nd -ix'legzg'ulzuiy roughened clue to the tearing' action.

In testimony whereof' ll' have hereunto signed my name in the pi'esenceof theto subscribed witnesses.

1 'JOHN W. .CORDES Witnesses: 2

CARL S. LAMB, WVM. J. PERTz. 

